${\sqrt[3]{686} = \text{?}}$
Explanation: $\sqrt[3]{686}$ is the number that, when multiplied by itself three times, equals $686$ First break down $686$ into its prime factorization and look for factors that appear three times. So the prime factorization of $686$ is $2\times 7\times 7\times 7$ Notice that we can rearrange the factors like so: $686 = 2 \times 7 \times 7 \times 7 = (7\times 7\times 7) \times 2$ So $\sqrt[3]{686} = \sqrt[3]{7\times 7\times 7} \times \sqrt[3]{2}$ $\sqrt[3]{686} = 7 \sqrt[3]{2}$